The demonstrated capability of Doppler ultrasound to detect particulate microemboli passing from cardiopulmonary bypass (CPB) circuits to the patient promises to assist in reducing the high incidence of stroke and other embolic complications from extracorporeal procedures. Our objective is to develop and market a line of Doppler products for vascular emboli detection. In this project we will: (a) refine and further test algorithms for on-line recognition and counting of Doppler-detected microemboli, (b) develop Doppler ultrasonic techniques for sizing and characterizing microemboli, (c) implement this technology by constructing Doppler devices, and (d) clinically test the first product in the line, a device to detect and count microemboli during CPB. This type of instrumentation will provide a valuable tool to: (1) indicate the presence of emboli, (2) guide the use of various prevention measures, (3) determine the effectiveness of these measures, and (4) expand knowledge of stroke and other vascular embolic disorders. PROPOSED COMMERCIAL APPLICATION: The project results will lead to unique instruments, first for automatically detecting and counting microemboli in extracorporeal tubing, second for sizing and characterizing microemboli in tubing, and third for noninvasively detecting, counting, sizing and characterizing microemboli in human arteries and veins.